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Article
Dosimetry Determines the Initial OH Radical Concentration in Fast Photochemical Oxidation of Proteins (FPOP)
Fast photochemical oxidation of proteins (FPOP) employs laser photolysis of hydrogen peroxide to give OH radicals that label amino acid side-chains of proteins on the microsecond time scale. A method for quant...
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Article
The Role of Methoxy Group in the Nazarov Cyclization of 1,5-bis-(2-Methoxyphenyl)-1,4-Pentadien-3-one in the Gas Phase and Condensed Phase
ESI-protonated 1,5-bis-(2-methoxyphenyl)-1,4-pentadien-3-one (1) undergoes a gas-phase Nazarov cyclization and dissociates via expulsions of ketene and anisole. The dissociations of the [M + D]+ ions are accompan...
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Article
New Protein Footprinting: Fast Photochemical Iodination Combined with Top-Down and Bottom-Up Mass Spectrometry
We report a new approach for the fast photochemical oxidation of proteins (FPOP) whereby iodine species are used as the modifying reagent. We generate the radicals by photolysis of iodobenzoic acid at 248 nm; ...
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Article
Gas-phase nazarov cyclization of protonated 2-methoxy and 2-hydroxychalcone: An example of intramolecular proton-transport catalysis
Upon CA, ESI generated [M + H]+ ions of chalcone (benzalacetophenone) and 3-phenyl-indanone both undergo losses of H2O, CO, and the elements of benzene. CA of the [M + H]+ ions of 2-methoxy and 2-hydroxychalcone,...
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Article
Protonated nitro group as a gas-phase electrophile: Experimental and theoretical study of the cyclization of o-nitrodiphenyl ethers, amines, and sulfides
A novel gas-phase electrophilic cyclization, initiated by the protonation of a nitro group, occurs for 2-nitrophenyl phenyl ether and for the analogous sulfide and amine, leading to heterocyclic intermediates ...
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Article
Structural determination of oxofatty acids by charge-remote fragmentations
A strategy is described to locate the carbonyl position in oxofatty acids by utilizing charge-remote fragmentations of various molecular ions that are desorbed by fast atom bombardment (FAB). Oxofatty acids we...